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Schottky contacts on p-type silicon, with embedded arrays of β-FeSi2 nanocrystallites, were studied by current-voltage (I-V), deep level transient spectroscopy (DLTS), and low-frequency noise measurements. Forward I-V characteristics on logarithmic scale indicate that space-charge limited current (SCLC) dominates the carrier transport in these diodes. From an analysis of the SCLC characteristics, we found that two arrays of β-FeSi2 nanocrystallites induce a trap level at 320 meV above the valence band edge with concentration of 5×1014 cm-3, which is in relatively good agreement with the trap detected by DLTS. By inserting ten arrays of β-FeSi2 nanocrystallites, two trap levels at 300 and 340 meV with concentrations of 2.6×1014 and 1.1×1015 cm-3, respectively, were found from the SCLC analysis. By increasing the number of the inserted arrays of β-FeSi2 nanocrystallites from 2 to 10, a trap at 402 meV with concentration of 6.5×1015 cm-3 has been detected by DLTS, failing to detect the second trap observed by SCLC measurements. The normalized power spectral density SI/I2 vs V exhibits a peak at the transition voltage from the trap-filling regime to the SCLC regime, corresponding to a deep trap level. It is demonstrated that the noise technique is more sensitive than the SCLC and DLTS techniques in extracting information about the deep trap parameters. [ABSTRACT FROM AUTHOR]

The structural and optical properties of thin Ge films deposited onto semiconducting and insulating substrates and modified by pulsed laser radiation are studied. The films are deposited by the sputtering of a Ge target with a low-energy Xe ion beam. Crystallization of the films is conducted by their exposure to nanosecond ruby laser radiation pulses (λ = 0.694 μm) with the energy density W = 0.2−1.4 J cm. During pulsed laser treatment, the irradiated area is probed with quasi-cw (quasi-continuous-wave) laser radiation (λ = 0.532 and 1.064 μm), with the reflectance recorded R( t). Experimental data on the lifetime of the Ge melt are compared with the results of calculation, and good agreement between them is demonstrated. Through the use of a number of techniques, the dependences of the composition of the films, their crystal structure, the level of strains, and the reflectance and transmittance on the conditions of deposition and annealing are established. [ABSTRACT FROM AUTHOR]

The electroluminescence efficiency of silicon light-emitting diode structures with several layers of β-FeSi nanocrystallites embedded in the p-n junction is investigated. The nanocrystallites were formed by either solid-phase epitaxy or a combination of reactive and solid-phase epitaxy. For the structures in which the nanocrystallites were formed by the combined method, electroluminescence is observed only at low temperatures (below 70K). This is indicative of a high concentration of defects acting as nonradiative-recombination centers. For the structures with nanocrystallites formed by solid-phase epitaxy, intense electroluminescence is observed up to room temperature. The dependence of the electroluminescence intensity on the size of the nanocrystallites is studied. [ABSTRACT FROM AUTHOR]

The initial stages of room-temperature Mg film growth of Si (111) were studied using low-energy electron diffraction, electron energy-loss spectroscopy, and differential reflectance spectroscopy. In the studied range of magnesium film thickness ( h = 0–0.2 nm), the formation of semiconductor magnesium silicide (Mg2Si), which is a promising material for silicon-silicide thermocouples, was detected. At small thicknesses of the deposited film, identical Mg2Si clusters are formed. An increase in the number of Mg atoms results in the formation of two-dimensional and then three-dimensional Mg2Si islands. Spectra of the optical response function δΛ″θ were measured for all structures; these spectra represent a characteristic of opticalproperties of these structures. [ABSTRACT FROM AUTHOR]

The in situ Hall effect measurements at room temperature showed that formation of the atomically clean Si(111) 7 × 7 surface as a result of high-temperature annealing (T = 1250°C, t = 120-180 s) of n-Si reverses the majority carrier sign at the surface, and a hole-enriched layer is formed at the p-Si surface. The different dynamics of Hall and resistivity voltage variations within the first monolayer of iron adsorbed onto substrates with ap-n junction or with a hole-enriched layer is not related to conduction over the adsorbed layer. Conduction in the Fe layer of thickness exceeding three monolayers is caused in both cases by the transport of electrons with densities 2 × 10[sup 13] -2 × 10[sup 14] cm[sup -2] and mobilities 65-90 cm² (V s). [ABSTRACT FROM AUTHOR]